/**
 * @file
 * Interface Identification APIs from:
 *              RFC 3493: Basic Socket Interface Extensions for IPv6
 *                  Section 4: Interface Identification
 *
 * @defgroup if_api Interface Identification API
 * @ingroup socket
 */

/*
 * Copyright (c) 2017 Joel Cunningham, Garmin International, Inc. <joel.cunningham@garmin.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Joel Cunningham <joel.cunningham@me.com>
 *
 */
 /*
* This file contains the implementation for RFC 2553/3493 section Section 4: Interface Identification
* The following functions are implemented
*  lwip_if_indextoname
*  lwip_if_nametoindex
*  lwip_if_nameindex
*  lwip_if_freenameindex
*  @note: when passing the ifname pointer to the function lwip_if_indextoname:
*  The ifname argument must point to a buffer of at least IF_NAMESIZE
*  bytes into which the interface name corresponding to the specified
*  index is returned.
*  IF_NAMESIZE is same as IFNAMSIZ and is of 16 bytes including null
*  The lwip_if_nameindex API can only support max 10 interface indexes. The index starts
*  from 1 and ends at 10.
*
*/
#include "lwip/opt.h"

#if LWIP_SOCKET

#include "lwip/errno.h"
#include "lwip/if_api.h"
#include "lwip/netifapi.h"
#include "lwip/priv/sockets_priv.h"

/*
 * @ingroup if_api
 * Maps an interface index to its corresponding name.
 * @param ifindex interface index
 * @param ifname shall point to a buffer of at least {IF_NAMESIZE} bytes
 * @return If ifindex is an interface index, then the function shall return the
 * value supplied in ifname, which points to a buffer now containing the interface name.
 * Otherwise, the function shall return a NULL pointer.
 */
char *
lwip_if_indextoname(unsigned int ifindex, char *ifname)
{
#if LWIP_NETIF_API
  if (ifindex <= 0xff) {
    LWIP_ERROR("lwip_if_indextoname:ifname is NULL", (ifname != NULL), set_errno(EFAULT); return NULL);
    err_t err = netifapi_netif_index_to_name((u8_t)ifindex, ifname);
    if (!err && (ifname[0] != '\0')) {
      return ifname;
    }
  }
#else /* LWIP_NETIF_API */
  LWIP_UNUSED_ARG(ifindex);
  LWIP_UNUSED_ARG(ifname);
#endif /* LWIP_NETIF_API */
  set_errno(ENXIO);
  return NULL;
}

/*
 * @ingroup if_api
 * Returs the interface index corresponding to name ifname.
 * @param ifname Interface name
 * @return The corresponding index if ifname is the name of an interface;
 * otherwise, zero.
 */
unsigned int
lwip_if_nametoindex(const char *ifname)
{
#if LWIP_NETIF_API
  err_t err;
  u8_t idx;
  LWIP_ERROR("lwip_if_nametoindex:ifname is NULL", (ifname != NULL), set_errno(EFAULT); return 0);
  err = netifapi_netif_name_to_index(ifname, &idx);
  if (!err) {
    return idx;
  }
#else /* LWIP_NETIF_API */
  LWIP_UNUSED_ARG(ifname);
#endif /* LWIP_NETIF_API */
  set_errno(ENODEV);
  return 0; /* invalid index */
}

/*
 * This function returns an array of if_nameindex structures, one  structure per interface.
 *
 * @param input None
 * @return if_nameindex*  The array of if_nameindex structures, one structure per interface
 *
 */
struct if_nameindex *lwip_if_nameindex(void)
{
#if LWIP_NETIF_API
  err_t err;
  struct if_nameindex *if_list = NULL;
  err = netifapi_netif_nameindex_all((void *)&if_list);
  if ((err == ERR_OK) && (if_list != NULL)) {
    return if_list;
  }
#endif
  set_errno(ENOBUFS);
  return NULL;
}

/*
 * This function frees the dynamic memory that was allocated by   lwip_if_nameindex().
 *
 * @param if_nameindex* The pointer to if_nameindex structure
 * @return None
 *
 */
void lwip_if_freenameindex(struct if_nameindex *ptr)
{
#if LWIP_NETIF_API
  if (ptr == NULL) {
    return;
  }
  mem_free(ptr);
#else
  LWIP_UNUSED_ARG(ptr);
#endif
}

#endif /* LWIP_SOCKET */
